I read the link and they defined the risk as when faulty wiring
comes into contact with a "grounded plumbing fixture". Bathrooms
and kitchens etc. certainly have grounded plumbing fixtures using copper
pipe so we can understand why they require special electrical breakers!
But outside rainwater or lawn sprinklers are not grounded.
What's the big fuss if a Coke machine gets wet?
I've been sellin' old Coke machines for 20 years and ain't never had
the lack of a GFCI hurt anyone! I doubt if I will change my ways now!